High energy fuel composition containing polybutadiene and borane



United States Patent 3 266 95s HIGH ENERGY FUEI. cbMPosmoN CONTAIN- ING POLYBUTADIENE AND BORANE Jack D. Breazeale, Grand Island, Charles F. Parks, Buf- This invention relates to reaction productsof polybutadiene rubbers and boranes.

Polybutadiene is a well known synthetic rubber material. Poly-butadiene is available, for example, as the products known as Butarez, a trade name of the Phillips Petroleum Company.

It has now been found that certain boranes can be combined with polybutadiene to form a solid material of high :boron content suitable for use as a propellant fuel for rocket power plants .and other jet propelled devices.

The fuels of this invention when incorporated with suitable oxidizers, such as. ammonium perchlorate, potassium perchlorate, sodium perchlorate, ammonium nitrate and etc., yield solid propellants suitable for rocket power plants and other jet propelled devices. Such propellants burn with high flame speeds, have high heats of combustion and are of the high specific impulse type. Probably the single most important factor in determining the perfor-mance of a propellant charge is the specific impulse. Appreciable increases in performance will result from the use of the higher specific impulse materials. The fuels of this invention when incorporated with oxidizers are capable of being formed into a wide variety of grains, tablets and shapes all with desirable mechanical and chemical properties. Propellants produced by the methods described in this application burn uniformly without disintegration when ignited by conventional means, such as the pyrotechnic type igniter and are mechanically strong enough to withstand ordinary handling.

An important advantage of the fuels of this invention is that they are elastic and hence resist cracking by heat and thermal shock. In practical use, solid propellants for jet propelled devices may be exposed to a variety of temperature conditions. Wide variations in temperatures cause thermal expansions which may induce cracking in the propellant grains. Similarly, physical shock experienced by the propellant grains both before and during their discharge in jet propelled devices may cause fracture and cracking of the grains. Such cracked propellant grains can be extremely dangerous to the jet propelled device in that they permit the grain to burn more rapidly in the immediate vicinity of the cracked section. The uneven burning rate which results may be so great as to cause an uneven thrust by the jet engine or an explosion in the rocket power plant. It is therefore very essential that the propellant used not be subject to fracture. Compounds having a rubber-like quality are particularly desirable for use in propellant grains because they can absorb both thermal .and mechanical shock without cracking or fracturing. The natural resiliency and elastic qualities of rubber-like materials make them ideal for resisting fracture. The fuel of this invention will not deteriorate when stored over a wide range of temperature conditions. It can be produced in a uniform composition, can easily be cast into grains and 'will not crack. In addition, the high percentage of boron which is present in the propellant com-position is in a readily burnable form and results in the release of much larger quantities of energy than the corresponding composition of carbon. The fuels of this invention need not use the conventional binding agent used by many other similar compounds to cause the oxidizer and fuel to adhere. The cohesive and tacky quality of the final product is sufficient to bind into a solid mass the granular oxidizing agent which is admixed with the fuel. Such mass will retain its form and elastic qualities when shaped into various configurations, and when cast into grains will adhere to the walls of the rocket case.

According to this invention, a polybutadiene is reacted with a suitable borane to produce solid materials useful as propellant fuels.

The polybutadiene rubbers suitable for use in this invention are solids or liquids. They include the known liquid and solid polymers obtained by polymerization of butadiene by various methods, e.g., sodium catalysis. The liquid products known as Butarez are particularly useful.

The physical properties of liquid polybutadiene (Butarez-15, Phillips Petroleum Company) are as follows:

Property: Value API gravity, 60 F 24.3 Specific gravity, 60 F 0.9083 Density, 60 F., lbs/gal. 7.5 Refractive index, n20/d 1.5198 'Iodine number 32.5 Color, Gardner 11 Volatile material, wt. percentage 1.0 Viscosity, SFV at F. 1500 The liquid polymerization product of butadiene as exemplified by Buta-rez-IS is primarily a linear polymeric chain built by random of 1,4 and 1,2 addition during the polymerization reaction of C-4 units of the two types indicated below: I

The polymer ordinarily contains 55 to 65 percent of 1,2 addition units and approximately 0.8 double bonds per (3-4 unit. Ultraviolet scanning techniques indicate the presence of conjugate structures of the naphthalenic type possibly derived from cyclization. Some cross-linking of the polymer chain is also evident.

The repeating formula of emulsion polymerized polybutadiene (a solid) is -(CH CH=CHCH The I physical properties are as follows:

Property: Value Density at 25 C. (G. per cc.) 0.89 Refractive index at 25 C 1.5148 Average mol. wt 100,000-200,000 Dilute solution viscosity 1.93 [1;] Intrinsic viscosity 2.08

A liquid emulsion polymerized polybutadiene can also be used.

Typical value Property:

Ash, percent 0.02 Moisture, percent 0.102 Dilute solution viscosity 0.18 Viscosity SFV at 210 F. 496

as described in pending application Serial No. 497,407, filed March 28, 1955, now Pat. No. 2,999,117, of Altwicker et al. and in pending application Serial No. 540,141, filed October 12, 1955, of Altwicker et al. now Pat. No. 3,109,030 wherein ferric chloride is used as the catalyst. Monoethyldecaborane can be also prepared by the reaction of decaborane and ethylene as described in pending application Serial No. 514,121, filed June 8, 1955, of Stange et al. Also, alkylated decaboranes such as monoethyldecaborane and diethyldecaborane can be prepared by reacting a mono-olefin hydrocarbon with a mixture of decaborane and an aluminum halide as described in pending application Serial No. 557,634, filed January 6, 1956, of Netf et al. now Pat. No. 2,987,552.

The polybutadiene is generally reacted with the borane at temperatures ranging from about 20 to 300 C. and pressures from about atmospheric to 1,000 p.s.i. The time of reaction varies from about 0.25 to 50 hours or more, depending on the temperature and pressur'e'employed. The borane is used in an amount of about 0.05 to 10 parts per part of polybutadiene, and preferably from 0.5 to 3.5 parts of the borane per part of polybutadiene. A solvent for the polybutadiene and inert to the reaction, e.g., methylcyclohexane, can be used if desired. The solvent can be used in amounts of from 0.001 to 100 parts of solvent per part of polybutadiene. The liquid polybutadiene can be reacted with the decaborane or alkyl decaborane with or without the use of a solvent. When solid polybutadiene is used, preferably it is dissolved in a solvent before reaction with decaborane or first plasticized, e.g., with alkyl decaborane, before reaction with decaborane.

The reaction product can be cured by carrying out the reaction under appropriate curing conditions of temperature and pressure or by first forming the reaction product and .then curing it. Curing agents such as decaborane or the alkyl decaboranes can be used as well as conventional cures, applicable to polybutadiene, e.g., a sulfur cure. The curing agents can be present during the reaction or used in a later curing step after separate formation of the reaction product.

For the preparation of propellant compositions containing an oxidizer, the oxidizer can be added to the reaction mixture, including the curing agent if it is present, and the reaction and curing carried out in the presence of the oxidizer or the oxidizer can be added to the separately formed reactionproduct before curing or the oxidizer can be added to the separately formed and cured reaction product, e.g., by intimately admixing it into the product.

The solid materials produced by the reaction of polybutadiene and the various boranes described above are 4 ta-ined was then filtered and subjected to reduced pressure (1 to 2 mm. of mercury) to remove the methylcyclohexane and was then extracted with pentane (100 ml.) to remove the unreacted decaborane. After removal of the pentane by subjecting to reduced pressure for 7 hours, a brown resilient material was obtained which was found, by Parr Bomb peroxide fusion analysis, to contain 3.74 percent boron.

' Example ll Solid emulsion polymerized polybutadiene (1.0 gram) dissolved in methylcyclohexane (20 grams) was placed with decaborane (1.0 gram) in a Chrome Vanadium Micro reaction vessel (American Instrument Company) of 110 cubic centimeters capacity. The autoclave was charged as above in a dry box then sealed and placed on a mechanism which permitted rocking during the heating period. The reaction mixture was maintained at a temperature of 250 C. for three hours, during which time the pressure in the sealed system increased from 80 to 150 pounds per square inch guage. After cooling the autoclave to room temperature, the product was removed and separated from the solvent by decantation. The product obtained was extracted with methylcyclohexane (100 ml.) to remove unreacted decaborane, and then was subjected to reduced pressure (1-2 mm. of mercury) for 7 hours to remove this solvent. A black resinous solid material was obtained which was found, by Parr Bomb peroxide fusion analysis, to contain 3.7 percent boron.

Example 111 5 grams of sodium polymerized liquid polybutadiene (Butarez-IS, Phillips Petroleum Company) was mixed with 20 cc. of methylcyclohexane and 1.0 gram of decaborane in a Chrome Vanadium Micro reaction vessel (American Instrument Company) of 110 cubic centimeter capacity. The autoclave was charged as above in a dry box, was sealed and placed on a mechanism which permitted rocking during the heating period. The reaction mixture was maintained at a temperature of 200 C. and at a pressure of pounds per square inch guage for 30 I minutes after which it was cooled to room temperature.

elastic or rubber-like to resinous solids of varying hardness and colors. Some are tacky. They are non-pyrophoric but burn readily on ignition. The solids contain a substantial amount of boron and with the boron admixed with or linked to the rubber molecule.

This invention will be further illustrated by reference to the following examples, wherein the polybutadienes used were those described above.

Example I Solid emulsion polymerized polybutadiene (1.0 gram) dissolved in methylcyclohexane (20 grams) was placed with decaborane (1.0 gram) in a Chrome Vanadium Micro reaction vessel (American Instrument Company) of 110 cubic centimeter capacity. The autoclave was charged as above in a dry box, then sealed and placed in a rocking mechanism which permitted rocking during the heating period. The reaction mixture was maintained at temperature of 150 C. for 3 hours at a pressure of 30-35 pounds per square inch guage after which it was cooled to room temperature. The pressure of the vessel after cooling was essentially atmospheric (similar to starting pressure) indicating no gas was evolved. The product obfor 7 hours to remove the excess solvent.

a syringe (in a dry box).

The product obtained was extracted with 100 ml. of pentane to remove unreacted decaborane and then subjected to reduced pressure (1 2 millimeters of mercury) A black, sticky material was obtained which was found, by Par Bomb fusion analysis, to contain 5.63 percent boron.

7 Example IV The preparation of the proposed fuel was started by dissolving decaborane (8.8098 .g.) in diethyldecaborane (349.283 g.). This solution then was mixed with solid emulsion polymerized polybutadiene (81.110 g.) in the following manner: a trial sample of polybutadiene (4.8 g.) was placed on a small hand operated mill and to this diethyldeca'borane (25 cc. or about 20.6 g.) was added from The mixture was found to be too fluid to'handle conveniently on this mill, so it was transferred to a Waring Blendor, which was swept with nitrogen. taining decaborane, and the polybutadiene were added in 7 increments with stirring. The mixture then was poured into a sample bottle and reserved for evaluation. Qualitative examination showed the material as prepared to be The remainder of the diethyldecaborane, con- 7 Examples V and VI A solution of 5.0 g. of sodium-polymerized liquid polybutadiene (Butarez-IS) and 2.5 g. of decaborane in 20 cc.

Soxhlet extractor, and then dried and weighed to determine :gel content, which was found to be 48.7 percent of the fuel mixture. The boron content of this gel portion of methylcylohexane was transferred to an American Instrument Company 406-35B6 Micro Reaction Vessel of 5 g 9 g Exanzples 110 ml. capacity. After flushing with nitrogen, the vessel escn e m a e ow wem per ormc m a sum at was sealed, placed on the rocking mechanism and heated manner Exam [e XVI at 200 C. for one-half hour at a pressure of 40 to 45 p p.s.i.g. The dark brown gelatinous material obtained was I washed with 50 cc. of n-pentane in four batches, and then 10 g ig i bsggfiagff i 5 3 filfi i g g 2:22:2 g g gi ggg z gfig fii tg 2:23: 52 3 323 agitated gently hours to form a solution. A solution sodium peroxide fusion to contain 16.35 percent boron. 25 3: 55; snethylamme m 15 benzene was added and a I l a V E xarlnple VI described in Table 1, was performed in a 15 In a nitrogen atmosphere, 8.1 g. of triethyldecaborane at manner was added, and the gray green mixtures were agitated Examples VII and IX gently 30 minutes. The benzene was removed by vacuum 'tion at room temperature for several hours. A synnge was used to add 8.9793 g. of triethyldecaevapora borane to 1.5005 g. of solid emulsion polymerized poly a: fi gg y 33 x gzf g g i butadiene in a mortar and pestle. After mulling to pro- $3 2 j or 2 duce intimate contact, the mixture was allowed to stand 0 e S m e o exc u e urmg 6 mo for about 96 hours. A portion of the tacky gum which The product was firm, tough, transparent and free of resulted was placed in a mold in a Carver press for 16 l It had a content of 27 percent f the hours at 55 C. The cured material thus obtained was Contained pence-1m boron' A Sample Sealed m an alrfound to contain 42 4 percent boron and to have a gel free glass tube (n trogen filled) possessed almost all of content of about 0.51 percent. Examples VII and VIII us original properties at 6momhs' described in Table 2 were performed in a similar manner. Examples XV" to XX Examplesxm 4 45 f Ph'll' ld 1 1 d 1 v g. o 1'1ps s01 emu s1on poymerize poyoffilg ifi g i g s g butatdiene was dissolved in 50 ml. of benzene. A nitrogen atmosphere was maintained, and 0.0114 g. of diphenyl-' glgg gg g ggsg gfg g gggjfi igr %i2fi W; iguanidine dissolved in l0 ml. .of benzene was added to I the polymer solution. Agitation was continued for 30 {tidied gogiiti} ggggzzlragafiz 13226151611011]? wi ls1 :ollztllg ffi minutes. Tllie mixture, in an 8 ounce screw cap'bottle,

was a s1rupy 1qu1 s g l g h was g a? gl g f d f d at The mixing apparatus consisted of 4 clamps attached coma-i1; 47 5 11;122:5 1 5 10 113122 g gi iogzgn to a shaft WhlCh oscillated in a 90 are at about cycles i per minute in a vertical plane. bIl if p l XII dGScnbed below 40 5.0 g. of monoethyldecaborane was added in the nitroe were P PII1 mas mannergen atmosphere of a glove box, and mixed on the above Examples XI to XV shaker for an additional hour. To a 200 m1 round gla s stopper d fl k dd d Benzene was removed by vacuum distillation at room s e as was a B tern nature, stirrin where necessa for a 0d 1.0101 'g. of solid emulsion polymerized polybutadiene, 41 g? g ry pen of followed y 10-0077 '8- of benzene- 0-0205 3- Of The residue was heated in a mold cavity at 60 C. for Sulfur a d 00 17 Of l/ Eight dithiocarbamate 3 hrs. The fuel was a soft elastic vulcanizate having a type ultra-accelerator) were added, the flask was swept gel value of 31 percent. The product was transparent with nitrogen, and 1.0694 g. of monoet-hyldecaborane was and yellow, and had a few bubbles of gas. added The benzene solvent was removed under reduced 50 The cured solid was preserved in glass withone atmospieasgrgrig abtout 2 hours jatth30; (13., leaving 2 .r1h288 g. phere of nitrogen and was almost unchanged in 6 months cen recov ry o e ue mix ure. e mat1me. rterial then was cured in an oven at C. for 16 hours, Examples XVIII, XIX and XX were performed in a scraped from the flask, andcut up into small pieces. similar manner,asdescribedinTable 5.

TABLE 1 Poly- Deon Methyl- Reaction Reaction Pres- 13mm in Example No. butaborane, cyclo- Time, Temp., sure, Prod.,

dlene, g. hexane, Hr. 0. p.s.i.g. Percent g. cc.

v 5. 0 2. 5 20 o. 5 200 40-45 16. 35 v1 5. 0 5. 0 20 0. 5 200 12-35 29. 73

TABLE 2 E 1 Example No. Alkylated Decaborane Alkylated P gl y curmg Cond- Cured Fuel Used Decaborane tadiene Amt.,g. Used, g. Time, Temp., Gel, Boron, Hrs. 0. percent percent VII Monoethyldecaboranennl 4. 7008 1.9981 16 55 15 49.7 vm Dlethyldecaborane 7.3515 1. 4599 2? 2 50.0 IX Triethyldeeaborane 8. 9793 1.5005 16 55 0. 51 42.4

TABLE 3 Borane- Ratio inMlx., g. Curing Cond. Cured Fuel Example Deca. Polybu- No. Added, Alk. deca. Used tadiene g. Mix. Por- Borane Polybu- Time, Temp., Gel, Boron,

tion, g. tadiene Hrs. 0. Percent Percent 0. 0113 Monoethyldecaborane. 1. 1131 4. 7008 1. 9981 16 55 24 47. 5 0. 0276 Dlethyldecaborane--- 2. 7774 7. 3575 1. 4.899 16 55 1 49. 7 0. 1921 'Iriethyldecaborane 6. 4224 8. 9793 1. 5005 16 55 43. 2

TABLE 4 Example Exam le Exam le XIII X? XV Bnr n Monoethyl- Diethyl- Triethyldecaborane decaborane decaborane Ingredients:

Borane, g. 1. 0694 0.9965 0. 9875 Polybutadiene, g 1. 0101 1. 0002 1. 0014 Sulfur, g 0. 0205 0. 0202 0. 0200 Butyl Eight, g 0. 0217 0. 0184 0. 0209 Benzene, g. 10. 0077 10.0070 10. 0027 Total Fuel, g 2. 1217 2. 0353 2. 0298 Solvent removed:

Benzene recovery, g 9. 2180 9. 4131 9. 2935 Fuel recovery, g 2. 1288 2. 0293 2. 0279 Benzene recovery, percent. 92. 2 94. 1 92. 9 Fuel recovery, percent 100. 3 99. 7 99. 9 Extraction:

Benzene, 1st addition, g 57. 9566 50. 7483 52. 5532 Benzene, 2d addition, g 42. 8111 43. 6021 42. 7189 Total Benzene, g 100. 7677 04. 3504 95. 2721 Recovered Benzene, g 97. 3290 90. 1261 90. 5733 Recovered Benzene, percent 96. 8 95. 95. 0 Gel Content:

Weight of Gel, g 1. 03 0.8759 0.8691 Gel based on Fuel, percent..- 48. 43. 0 42. 8 Gel based on Polymer, percen 102. 87. 6 86. 9 Boron in Gel, percent 2. 41, 2. 1. 53, 1. 08 1. 11, 1. 07

TABLE 5 Mixture Example XVII Example XVIII Example XIX Example XX Polybutadlene, g 4.45. 3.4.- 2.35 4.05. Benzene, ml 50 50 50 50. Diphenylguanidiue, g 0.0114 0.0085 0 0059 0.0101.

Borane Monoethyldecaborane Diethyldecaborane r e mon yl bo m'ie. Borane, g. 6.6 7 65 5.95. Boron, percent calculated 40 40.- 40 40. Physical properties Soft, elastic vulcanizate. Soft, elastic vulcanizate Soit, elastic vulcanizate. Gel Value percent 31. 2i 15 33. Boron in el, percent 1.5-. 1.9.- 1.6. After storage for 6 months Almost unchanged Almost unchanged Almost unchanged.

1 Containing 65.1% monethyldecaborane, 29.7% diethyldecaborane, 4.0% triethyldecaborane and 1.0% deeaborane.

The ethyldecaboranes used in Examples IV and VII to XX were obtained from a Fricdel-Crafts reaction of decaborane-14 (B H and an ethyl halide, in the presence of a ferric chloride catalyst. The product of this reaction consisted of a mixture 01f ethyldecaborane, diethyldecaborane and tricthyldecaboranc. These constituents were separated -by a fractional distillation at reduced pressures. At a pressure out about 0.2 mm. Oif mercury, monoethyldecalborane boils at approximately 30 C., dicthyldecaiborane at C. and triethyldeca'borane at 65 C. 'By this method of separation products were obtained having a purity of greater than 99 percent.

The boron containing solid materials produced by practicing the method of this invention can be employed as ingredients of solid propellant compositions in accordance with general procedures which are well understood in the art, since the solid materials are readily oxidized using conventional solid oxidizers, such as ammonium I perchlorate, potassium perchlorate, sodium perchlorate, aluminum perchlorate, lithium perchlorate, ammonium nitrate and the like. :In formulating a solid propellant composition employing one 015 Ithe materials produced in accordance with the practice of this invention, generally [from 10 to 35 parts by weight of the boron-containing material of this invention and from 65 to 90 parts by weight of oxidizer such as ammonium perchlorate are present in the final propellant composition.

The polybutadiene-borane reaction product can be subdivided by means of conventional equipment designed to reduce the size of resilient materials, e.g., such devices which cut, chop or tear the feed material int-o a divided product as the wellknown rotary knife cutters and granu-lators. The oxidizer can [be reduced in size !by conventional equipment, c.g., a hammer mill. In formulating,

a propellant the finely divided reaction product and oxidizer' can then be intimately admixed in conventional mixing equipment employing rotating blades, e.g., kneaders or Baker-Perkins mixers, along with a binder such as an additional quantity of polybu-tadicne, or other rubber and curing agents. This resulting intimate admixture can then be cast or pressed into the desired form and cured.

Propellant compositions can also be prepared 'by intimately admixing the polylbutadiene, the borane, the oxidizerand other conventional curing agents if desired and curing this resulting intimate admixture.

In addition to the oxidizer and oxidiza ble material, the final propellant can contain another ibinder as previously stated. A binder of an artificial resin type, such as phenol-iformaldehyde, is useful. The 'function of this resin isto give the propellant mechanical strength and at the tent solution of a partially condensed phenol-\foumal'dehyde resin, the proportion being such that the amount of the resin is about from to percent by weight, based upon the weight of the oxidizer and the boron material.

The ingredients are thoroughly mixed with the simultaneous removal of the solvent, e.g., by use of a vacuum, and following this the solvent-tree mixture is molded into the desired shape as by extrusion. Thereafter, the resin in the mixture can be cured, e.g., by heating at moderate temperatures, e.g., SO-200 C. Conventional and suitable methods of tormulation of solid propellant compositions are further described in U.S. Patent 2,622,277 of Bonnell and US. Patent 2,646,596 of Thomas.

The following examples illustrate the (formulation of solid propellant compositions utilizing the solid boroncontaining reaction product of this invention which has been prepared without incorporation of oxidizer.

Example XXI pounds of the solid boron-containing material of Example II (mean particle size 840 microns) and 80 pounds of ammonium perchlorate oxidizer (mean particle size 840 microns) are introduced into a Baker-Perkins mixer along with 10 pounds of a solution of a phenol formaldehyde resin in toluene and the three components intimately admixed with the simultaneous removal of the solvent by means of a vacuum. The, resulting solventfree homogeneous solid is molded or extruded and cut into cylindrical grains of about 2 inches in diameter and 3 inches in length. The grains are then heated in an oven to about 100 for the necessary time to cure the resin in the grains. The resulting grains are an intimate admixture of solid fuel and oxidizer with resin binder.

The product of this invention can be utilized in its extracted form, that is, after the uncombined decaborane or lower alkyl decaborane has been removed from the final reaction product by extraction with a suitable solvent. The unextracted reaction product, however, can also be advantageously used as a propellant. The unextracted product contains a quantity of decaborane or lower alkyl decaborane homogeneously dispersed throughout. When combined with an oxidizerin the manner previously described and ignited, both the combined product and the decaborane or lower alkyl decaborane burn readily. The unextracted product has the advantage ofcontaining a higher percentage of boron (an element having a high heat of combustion) homogeneously dispersed in a form which can be easily admixed with a suitable oxidizing agent and which will burn liberating a larger quantity of energy than the extracted product.

What is claimed is:

1. A solid high energy fuel composition consisting essentially of the product of reaction of polybutadiene rubber and a borane selected from the group consisting of decaborane and lower alkyl decaboranes and mixtures thereof at a temperature of about 20 to 300 C. and in amounts of about 0.05 to 10 parts by weight of borane per part of polybutadiene rubber.

2. The composition of claim 1 in which the borane is' decaborane.

, 3. The composition of claim 1 in which the borane is diethyldecaborane.

4. The composition of claim 1 in which the borane is monoethyldecaborane.

5. The composition of claim 1 in which the borane is triethyldecaborane.

6. The composition of claim 1 in which the polybutadiene and borane are reacted in an amount of about 0.5 to 3.5 parts of borane per part of polybutadiene.

7. The composition of claim 6 in which the borane is decaborane.

8. The composition of claim 6 in which the borane is diethyldecaborane.

9. The composition of claim 6 in which the borane is monoethyldecaborane.

10. The composition of claim 6 in which the borane is triethyldecaborane.

. 11. The method of preparing a solid high energy fuel composition which comprises reacting polybutadiene rubber with a borane selected from the group consisting of decaborane and lower alkyl decaboranes and mixtures thereof at a temperature of about 20 to 300 C. and in amounts of about 0.05 to 10 parts by weight of borane per part of polybutadiene rubber.

12. The method of claim 11 in which the borane is decaborane.

13. The method of claim 11 in which the borane is diethyldecaborane.

14. The method of claim 11 in which the borane is monoethyldecaborane.

15. The method of claim 11 in which the borane is triethyldecaborane.

16. The method of claim 11 in which the polybutadiene and borane are reacted in amounts of 0.5 to 3.5 parts of borane per part of polybutadiene.

17. The method of claim 16 in which the borane is decaborane.

18. The method of claim 16 in which the borane is diethyldecaborane.

19. The method of claim 16 in which the borane is monoethyldecaborane.

20. The method of claim 16 in which the borane is triethyldecaborane.

21. A solid high energy fuel composition consisting I essentially of the product obtained by reacting at a temperature of to C. equal proportions of polybutadiene and decaborane.

References Cited by the Examiner UNITED STATES PATENTS 6/1951 Hurd et al. 5/1957 Moore et al.

OTHER REFERENCES BENJAMIN R. PADGE'IT, Acting Primary Examiner,

LEON D. ROSDOL, ROGER L. CAMPBELL,

Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,266,958 August 1 9 Jack D. Breazeale et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 22, for "32.5" read 325 column 4, line 28 for "5.7" read 33 7 Signed and sealed this 1st day of August 1967.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents EDWARD M. FLETCHER, JR.

Attesting Officer 

1. A SOLID HIGH ENERGY FUEL COMPOSITION CONSISTING ESSENTIALLY OF THE PRODUCT OF REACTION OF POLYBUTADIENE RUBBER AND A BORANE SELECTED FROM THE GROUP CONSISTING OF DECABORANE AND LOWER ALKYL DECARBORANES AND MIXTURES THEREOF AT A TEMPERATURE OF ABOUT 20 TO 300*C. AND IN AMOUNTS OF ABOUT 0.05 TO 10 PARTS BY WEIGHT OF BORANE PER PART OF POLYBUTADIENE RUBBER. 